Thermostatic control switch



y 1933- A. CHRISTENSEN 2,124,999

THERMOSTATIC CONTROL SWITCH Filed June 24, 1937 h v 2| as 25 5 INVENTORI7 34 2O 35 I9 26 24 23 3O 45 AXEL CHRISTENSEN ATTORNEYS Patented July26, 1938 2,124,999-

UNITED STATES PATENT OFFICE THERMOSTATIO CONTRQL SWITCH AxelChristensen, Racine, Wis.

Application June 24, 1937, Serial No. lll,l28

3 (Claims. (ill. 209-137) This invention appertains to control devices,spending parts throughout the several views, the and more particularlyto a thermostatically regletter C generally indicates the improvedcontrol, ulated control switch capable of general applicawhich embodiesa protecting housing or casing tion, and particularly adapted for use inconill. The inner end wall of the casing has conjunction with boilershaving oil burners, stolrers, nected therewith a coupling nipple l l.The nip- 5 5 and the like. I v pine l l is in turn secured to theappliance l2, the

One of the primary objects of my invention is temperature of which is tobe controlled. to provide a control device of exceptionally sim- Theappliance it in the present instance may ple and durable construction,one that will he be considered as a hot water boiler. The horisensitiveto temperature changes, and one which zontally extending bore E3 of thenipple ii is it can be easily and quickly associated directly withenlarged at its inner end, as at and this the appliance to becontrolled. Another salient portion of the bore receives and supportsthe object of my invention is to provide an efficient heat responsivemeans it. mechanism for manually setting the switch to The heatresponsive means it includes a tube 5 the temperattu'e that is desiredto he maintalnec, it formed from a metal possessing a high coeifiwherebythe device will be capable of controlling cient of expansion and aninner rod ll formed a wide range of temperatures. from a material havinga low coefficient of ex- Aiurther important object of my invention ispanslon. The rod ii is anchored to a head ill to provide a controldevice embodying a rner-= rigidly connected to the inner end of thetube,

cury switch pivotally mounted at one end and an and the rod ll extendsthrough the bore and operating lever supporting the other end actuintothe casing ill. atecl from a heat sensitive expansion element i Rigidlysecured to-the lower wall of the casing tilting the switch, with meansfor manually shiftit is a longitudinally extending ii-shaped guide ingthe switch and lever bodily toward and away bracket it], the legs ill ofwhich are apertured for from said heat sensitive element, whereby toacslidahly receiving a slide bar ill. The outer end 25 curately controlthe throwing of the switch when of the slide bar 26 has anchoredthereto, by a desired temperature is reached. means of a cross-bar 22,upstanding arms A still further object of my invention is to pro- Thearms in turn support pivot pins E l on vide a control device in whichwear will he re which is roclrably mounted a supporting plate 39 ducedto a rm'nirnum and all lost section elim- Secured to the plate 25 bymeans of a suit- 30 inated. able clip 26 is a tube or bulb 2'l having aglobule With these and other objects in view, the inof mercury 28 orother electric conducting mate vention consists in the novelconstruction, airial therein. The plate and bulb extend inwardrangement,and formation or" parts, as will be 1y of the pins 2 and hence, ineffect, he bulb hereinafter more speciflcally described, claimed, isroclrably mounted at its outer end. 'l'nis end 35 and illustrated in theaccompanying drawing, in has anchored therein a pair of spaced contactswhich drawing: 29 to "which are connected electric wires til. The Figure1 'is a longitudinal sectional view electric wires 3% are in turnconnected by means through the improved control device. of binding poststo spaced conducting plates 40 Figure 2 is an end elevational view ofthe eon= 32, to which are secured conductor wires lead- 49 trol device.ing to a source of electrical energy and the device Figure 3 is anenlarged, detail sectional view to be controlled, such as an electricmotor of an taken on the line of Figure 1, looking in the oil burner ora coal stoker.

direction of the arrows, illustrating the means Obviously, when theinner end of the bulb 2? for rockably supporting the actuating lever. isin a lowered position, the globule of mercury Figure 4 is an enlarged,fragmentary, detail rides away from the contacts 29 to open a sectionaltaken substantially on the line circuit. and when the inner end of thebulb is of Figure l, looking in the direction of the in an elevatedposition, the globule of mercury arrows, illustrating the mounting oi.the mercury will bridge the contacts 253 and close a circuit. 00 switch.The forward end or the slide bar 2i has an- Figure 5 is a fragmentary,top plan view illus chcred the eto the forwardly extending brackettrating the mounting of the actuating lever and 35 on which isrockably'mounted the forward the mercury switch on the slide bar. end ofthe actuating lever 35. .The lever ex" Referring to the drawing indetail, wherein tends toward the front of casing from its 5 similarreference characters designate corre= pivot pin and terminates in anupwardly curved on or secured to a traveling screw 66.

bearing head 35 on which rests the plate 25 carrying the bulb. The innerend of the actuating lever has formed thereon or secured thereto adepending bearing lip M, which extends below the pivot for the'lever,and this lip is adapted to engage the end of the operating rod ll, whichextends into the casing.

Manual means is provided for shifting the slide rod 2!, whereby theposition of the lever 36 and the bulb 2? can be varied relative to theoperating rod H. The means for manually shifting the position of theslide bar at includes an operating shaft 38. This shaft 38 is rotatablymounted in a suitable bearing ea carried by a removable portion at ofthe casing. The outer end of the shaft 38 has firmly secured thereto adial disc ii and an operating knob 32. The dial disc is graduated in thedesired manner, and a pointer 63 for cooperating with the dial'disc iscarried by the casing.

Secured to the inner end of the operating shaft 38 is an elongated spurgear M, which has constantly meshing therewith a relatively thin spurgear 35. The spur gear $5 is of a greater diameter than the spur gear58, and is formed This screw 46 is threaded into a guide sleeve =i'lcarried by the casing. A suitable bearing knob 48 is carried by thescrew 46 and bears against the outer end of the slide rod.. The sliderod is normally held in contact with the bearing knob 48 at all times bya contractile coil spring 59. The

' opposite ends of this spring are suitably anchored to the slide bar 2!and to the bracket i9.

From the description so far, it can be seen that upon the turning of theshaft 38 by the knob 42, the screw 46 will be moved in or out, whichwill bring about the shifting of the slide bar. This shifting of theslide bar will vary the position of the actuating lever 35 relative tothe operating rod ll.

41 use of my improved device, the knob 42 is turned until the dial disctravels to the temperature indicated on the disc, at which the heat isto be maintained. This brings about the initial adjustment of the lever35. As the appliance l2 increases in temperature, the tube l8 willexpand, and the head l8 will gradually draw the rod i'l away from thelip 31.

When a predetermined temperature for which the device is set is reached,the'rod l'l will permit the inner end of the lever 35 to lower, and thebulb 21 will swing down, as shown in Figure 1. The globule of mercurywill consequently roll away from the contacts 29. As the temperaturelowers, the tube It will contract and the rod l1 araaaaa will begradually carried inwardly, which will swing up on the inner end of thelever 35, and

when the bulb 2? is again raised to an elevated position, the globule ofmercury will flow down the tube-into engagement with the contacts.

The construction of my device is such that the operating lever 35directly supportsthe mercury switch. This eliminates friction and lostmotion, and upon manual adjustment, the lever and switch aresynchronously moved toward and away from the operating rod as a unit.

Changes in details may be made without departing from the spirit or thescope of my invention, but what I claim as new is:

1. In a control device of the character described, heat-responsive meansmovable upon temperature change, a slide bar, a control switch rockablymounted at one end upon the slide bar, an actuating lever movable bysaid heat responsive member rockably mounted on the slide bar,

and supporting said switch at a point remote. from its pivot point, andmeans for varying the position of the slide bar.

2. Ina control device of the character described, heat-responsive meansmovable upon temperature change, a longitudinally movable with thetraveling screw, and manual means including a dial and a pointer forrotating the screw.

- 3. In a control device of the character described, heat-responsivemeans movable upon temperature change, a guide bracket, a slide barmounted in said bracket and movable longitudinally toward and away fromthe heat-responsive means, a supporting plate rockably mounted upon theslide bar, a mercury switch on said plate, means detachably securing theswitch to the plate, said switch projecting forwardly from the pivotpoint of the plate, an actuating lever rockably mounted on the inner endof the slide bar including an elongated arm engaging the plate at apoint remote from its pivot, and a depending short arm engaging a partof the heat-responsive means, a traveling screw, spring means normallyurging the slide bar into engagement with the screw, and manual meansfor turning the screw.

AXEL CHRISTENSEN.

